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Reynolds, Mach, and Freestream Turbulence Effects on the Flow in a Low-Pressure Turbine

Fiore, Maxime and Gourdain, Nicolas Reynolds, Mach, and Freestream Turbulence Effects on the Flow in a Low-Pressure Turbine. (2021) Journal of Turbomachinery, 143 (10). 101009-1010022. ISSN 0889-504X

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Official URL: http://doi.org/10.1115/1.4050919

Abstract

This article presents the large-eddy simulation (LES) of a low-pressure turbine (LPT) nozzle guide vane (NGV) for different Reynolds (Re) and Mach (Ma) numbers with or without inlet turbulence prescribed. The analysis is based on a slice of an LPT blading representative of a midspan flow, where secondary flows, hub, and shroud effects are lower. The characteristic Re of the LPT can vary by a factor of four between take-off and cruise conditions. In addition, the LPT operates at different Ma values, and the incident flow can have significant levels of turbulence due to upstream blade wakes. This article investigates numerically using LES the flow around an LPT blading with three different Reynolds number Re= 175,000 (cruise), 280,000 (mid-level altitude), and 500,000 (take-off) keeping the same characteristic Mach number Ma = 0.2 and three different Mach number Ma= 0.2, 0.5, and 0.8 keeping the same Reynolds number Re= 280,000. These different simulations are performed with 0% freestream turbulence (FST) followed by inlet turbulence (6% FST). The study focuses on the influence of these three parameters (Re, Ma, and upstream turbulence) on different flow characteristics: pressure distribution around the blade, near-wall flow behavior, loss generation, and turbulent kinetic energy (TKE) budget. The results show an earlier boundary layer separation on the aft region of the blade suction side when the Re is increased, while the increase of the Ma delays separation, similar to freestream turbulence. The TKE budget led on the different cases shows the predominant effect of the turbulent production and diffusion in the wake, the axial evolution of these different terms being relatively insensitive to Re and Ma.

Item Type:Article
HAL Id:hal-03238795
Audience (journal):International peer-reviewed journal
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Institution:Université de Toulouse > Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE)
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Deposited On:27 May 2021 09:27

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